Motor Circuit Analysis & Electrical Signature Analysis

Motor Circuit Analysis (MCA™) is a de-energized test method that enables a motor diagnostics technician to determine the condition of the electric motor windings. A low voltage, non-destructive AC signal is sent through the motor windings to measure the response to these signals. The phase angle (Fi), the current/frequency response (I/F), the impedance (Z), the resistance (R) and the inductance (L) of each winding is measured and the unbalances of these measurements are compared.

Winding faults are indicated by variances in the response to the applied signal through the windings. These variances cause unbalances in the measured response to the applied signal. Therefore, when testing 3-phase equipment such as motors, generators, or transformers, the response of each phase is compared to the other two. When testing single phase devices or DC motors, then the winding is compared to itself or compared to a like single phase device or a like DC motor.

Phase resistance is evaluated to determine connection issues;

Inductance is evaluated for possible rotor problems;

Impedance and inductance matching are used to detect contamination or over-heating of the windings;

Electrical Signature Analysis (ESA) is an energized test method where voltage and current waveforms are captured while the motor system is running. Faults related to incoming power, the control circuit, the motor itself, and the driven load are detected via a Fast Fourier Transform (FFT) and can then be trended for Condition Based Maintenance/Predictive Maintenance purposes.

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[…] incursion into the bearings as well. Monitoring the electrical insulation condition with motor circuit analysis will allow of early detection of winding contamination build up within the electric motor on the […]